Switch unit



July 16, 1957 w. a. STECH 2,799,785

SWITCH UNIT Filed April 19, 1955 2 Sheets-Sheet 1 INVENTOR. WILLIAM G. STECH ATTORNEY July 16, 1957 w. G. STECH 2,799,785

SWITCH UNIT Filed April 19, 1955 2 Sheets-Sheet 2 FIG.3

76 5| 4| 2 7 r06 2 i 48 INVENTOR.

42 WILLIAM G.STEGH 4 BY 33 27 7a 77 W W F|G.6 ATTORNEY United States Patent SWITCH UNIT William G. Stech, Cleveland, Ohio Application April 19, 1955, Serial No. 502,436

Claims. (Cl. 307-112) This invention relates to electroplatingapparatus, and more particularly to an improved switch unit or switch means for controlling the plating current.

It is well known that in electroplating articles the plating thickness will vary with the plating time if other factors such as the current density in the electrolyte bath and the temperature and specific gravity of the bath are closely controlled. Accordingly, for uniform plating thickness it is highly important that the plating time be accurately controlled. It is common practice to have a single operator supervise several plating tanks wherein a visible or audible signal is given to indicate completion of a desired plating period whereby the plating current is cut off by manual operation of switches. For various reasons, the operator does not immediately cut oil the plating current in many instances resulting in excess plating time which not only causes waste of expensive plating material but excess plating thickness, particularly on small threaded articles, frequently results in high rejection of the plated articles. I have provided an improved switch unit adapted to automatically control the plating time.

I am aware that it has previously been suggested to automatically control the plating period by providing an A. C. interval timer comprising an A. C. synchronous motor operating an A. C. relay mechanism which controls the main switch. My improved unit permits a relatively inexpensive clock type timer, energized by manual setting of the desired plating period, to be inserted in the D. C. circuit to cut olf the plating current.

Also, I am aware that a singleswitch unit has previously been suggested to control the plating current but due to the heavy amperage required in electroplating the switch units with which I am familiar are bulky, of heavy construction, and relatively expensive.

I have developed a switch unit for controlling plating current which-is compact, relatively inexpensive, and is adaptable to being operated by conventional relatively inexpensive manually energizable time clock mechanism. The switch unit has particular advantages when a plurality orbattery of plating tanks are being used. Further, the unit is adaptable to conventional electroplating apparatus of either the-six or twelve volt D. C. type.

It is a primary object of the invention to provide a switch unit for controlling electroplating current or the like which is relatively inexpensive, compact, and universally adaptable to conventional plating apparatus.

Anotherobject of theinvention is to provide a switch unit of'the above type adapted to use inexpensive clock timer means for automatically controlling the plating time.

Other objects of the invention and the invention itself will become increasingly apparent from a consideration of the following description and drawings wherein:

Figure 1 is a view, largely diagrammatic, of electroplating apparatus embodying the invention;

Figure 2 is a wiring diagram ofthe 'switchunit and associated parts;

Figure 3 is a left side elevational view of the unit;

Figure 4 is a front elevational view of the unit;

Figure 5 is a right side elevational view of the unit; and

Figure 6 is a fragmentary wiring diagram of a modification of the invention.

The switch unit to be described is particularly adapted to barrel plating of articles such as applying a coating of zinc, cadmium, copper, tin or the like but is also adaptable to certain types of still plating such as chrome plating.

Referring now to the drawings, and particularly Figure l, I have indicated at 10 a conventional plating tank in top plan view. The tank has a perforated barrel or cylinder 11 mounted therein which during the plating operation is adapted to be rotated in the usual manner by means (not shown). The tank has the usual flexible contacts 15 disposed therein.

A motor-generator set 12 supplies direct current by a line 13 to tank 10 under control of my improved switch unit generally indicated at 14. It is understood that a rectifier associated with a suitable source of A. C. current may be used instead of a motor-generator set for supplying the D. C. current. Line 13 is connected with rods 17 which support elongate receptacles 18 for the plating material, preferably in the form of anode balls 19. A line 16 or cathode lead extends from tank 10 to switch unit 114 and upon closing of the switch current will pass through the plating solution, cathode horn 21, saddle 22, line 16, unit 14, and line 23 to the negative or low potential side of the generator to complete the circuit.

With the exception of the switch unit 14 all the apparatus so far described is well known and only a brief description of this apparatus is given herein. The switch unit which is the essential part of the present invention will now be described and is best illustrated in Figures 3, 4 and 5.

A rear bus bar 26 is adapted to be connected to line 16 which leads from tank 10 and a front bus bar 27 is adapted to be connected to line 23 which leads to the negative side of the generator. Two banks of solenoid operable switches are disposed between the bus bars, each switch being connected to the bus bar in a similar manner whereby one contact of each switch is directly connected to bus bar 26 and the other contact to bus bar 27. Upon the contacts being bridged by energizing or deenergizing the associated coil of the electro-magnetic switch, current will be permitted to flow from bus bar 26 to bus bar 27. The coils of each bank of switches are connected in parallel whereby the switches of each bank will be concurrently closed or opened. Any suitable type of solenoid switch may be used but I have found that solenoids of the type used for automotive starting and having a six volt continuous duty coil with a rating of one-hundred amperes are very satisfactory since they are rugged and relatively inexpensive.

The left hand bank of coils (Figure 4) is generally indicated at 2?; and the right hand bank at 23". The top switch of bank'ZS is indicated at 31 and has a lateral threaded contact arm 32 bolted to bus bar as and an oppositely extending contact arm 33 bolted to bus bar 27. All the solenoid switches, three being illustrated for each bank, are connected in like manner to the bus bars. Each switch has a pair of threaded coil terminals extending through the switch housing as indicated at 34 and 36 (Figure 5) and all the terminals 36 of bank 29 are bolted to a conductor 37 and the terminals 34 to a conductor 38. It will be noted that conductor 37 is connected to bus bar 26, as indicated at 39, and it will be apparent that upon a circuit being completed through conductor 38 the coils of all the switches in bank 29 will be energizedito operate the switches and either permit or interrupt current flowfrom bus bar 26 to bus bar 27.

In a similar manner the switches of bank 28 will be concurrently operated when a circuit is completed through conductors 41 and 42. Although I have illustrated three switches in each bank it is understood thata greater number may be used for increased plating current since the unit illustrated is designed to operate with a maximum current of approximately 500 amperes.

A blower 43, preferably of the centrifugal type, is mounted to direct cooling air between the bus bars and over the solenoid switches. The air inlet is indicated at 44, the exhaust at 46, and the blower motor 47 which is preferably a 12 volt D. C. type.

A green signal light is indicated at 48 and a red signal light at 49 for purposes to be described, the green signal preferably being a six volt lamp and the red signal a twelve volt lamp.

A conventional time clock type switch 51 has a fixed dial '2 indicating minutes, an adjustable stop 53, and a rotatable arm 54 whereby when the stop is set for a desired plating time (such as fifteen minutes) and the arm is manually advanced from zero against the stop to close the switch a spring will be wound to provide energy for opening the switch when the arm 54 is automatically rotated counter-clockwise back to zero position. This type of switch is relatively inexpensive and is adapted to be used with the switch unit 14 to accurately control the plating time. A switch, generally indicated at 50 is adapted to throw banks 28 and 29 of the solenoid switches in either parallel or series relation in a manner to be fully described.

Referring now to the wiring diagram (Figure 2), for clcarness of illustration, only the contact arms 32 and 33 of solenoid switch 31 are shown but it is understood that the remaining solenoid switches have similar contact arms connected to bus bars 26 and 27. As previously explained the switch unit is adapted to be used with either a six volt or twelve volt conventional plating system. Assuming the system is designed to operate on twelve volts and that the desired plating time for articles disposed in barrel 11 is fifteen minutes. After the barrel has been loaded and disposed in the electrolyte bath or tank the stop 53 of clock switch 51 is adjusted to fifteen minutes and arm 54 is rotated to a position against the stop which closes switch 51 and manually loads a spring adapted to open the switch at the expiration of fifteen minutes or when arm 54 has moved counterclockwise back to zero (Figure 4). One contact of switch 51 is connected by a lead 56 to conductor 41 of solenoid switch bank 28 and one terminal of blower motor 47 is connected to lead 56. A lead 58 extends from conductor 42 of bank 23 to a pole 59 of switch 59. The other terminal of blower motor 4-7 is connected as indicated at 57 with a lead 69 which extends from the switch arm of clock switch 51 to bus bar 27.

A lead 61 connects conductor 38 of solenoid switch bank 2, with an arm 62 of the double throw switch 50.

It will now be apparent that if switch 50 is thrown to connect arm 62 with pole 59 that solenoid switch banks 29 and 28 will be connected in series since a circuit will be completed from lead 16, bus bar 26, conductor 37, through the coils of the solenoid switches of bank 29 to conductor 33, leads 61, lead 58, conductor 42, through the coils of the solenoid switches of bank 28 to conductor 41, lead 56, clock switch 51, and lead 60 to .bus bar 27.

Completing the circuit as described will close all the solenoid switches and provide six parallel paths of current flow between bus bars 26 and 27 and if the maximum plating current does not exceed 500 amperes each solenoid switch will be carrying somewhat less than its rating of 100 amperes at 12 volts. 7

It will be noted that green signal lamp 48 is connected with lead 58 and conductor 41 so that when a circuit as described is completed through conductors 41 and 42 the lamp will light indicating the solenoid coils are energized I and the plating process is in operation. Also, it will be 4 noted that red signal lamp 49 is connected across bus bars 26 and 27, as indicated at 71 but the lamp will not light when the solenoid switches are closed due to negligible current flow with switch 51 closed. However, upon opening of clock switch 51 lamp 49 will light giving a visible indication to the operator that the plating period has terminated and the signal will continue although the plating current through the solenoid switches has been cut off, until the operator throws switch 50 to neutral position.

During the time the solenoid switches are engaged the blower will operate to cool the solenoid coils and the blower will continue to operate after the solenoid switches open until switch 50 is thrown to disengage switch arm 62 from pole 59 since although the effective plating current is cut off by opening of clock switch 51 sufiicient current can flow through the solenoid coils to operate the blower motor. The additional cooling etfect until the operator is available to remove the plated articles from the tank is highly desirable since coil burn-out is a serious problem. a

If it is desired to use the switch unit with a six volt plating system solenoid switch banks 28 and 29 are connected in parallel by throwing switch 50 to engage arm 62 with a pole 63 and arm 66 with a pole 68, after clock switch 51 is closed. In this case the circuit for bank 29 is from bus bar 26 to conductor 37 and through the solenoid coils to conductor 38, lead 61, switch arm 62 with pole 63, lead 64 to conductor 41, lead 56, clock switch 51, and lead 60 to bus bar 27. The circuit for bank 28 is from bus bar 26 to conductor 37, lead 67 to switch arm 66, pole 68 and lead 69 to conductor 42,

through the solenoid coils of bank 28 to conductor 41,

and then lead 56, clock switch 51 and lead 60 to bus bar Inasmuch as current will flow through conductors 41 and 42 the green signal light will operate as previously explained to indicate that the solenoid coils are energized and the plating process is in operation. Also, when the clock switch 51 opens the red lamp will light as previously explained to indicate that the plating period has terminated and the solenoid switches are open. Further, the blower will operate during the plating period and thereafter until switch 50 is opened.

The blower is primarily necessary since the solenoid coils are energized and must be cooled all during the plating period or during the time the coils are carrying current to avoid burning the coil insulation. The solenoid switches so far described are of the type known as normally open switches which are normally held open by spring pressure and are only closed when coils are energized. However, I contemplate that normally closed solenoid switches may beused wherein the switches are normally held closed by spring pressure are are opened when the coils are energized. Figure 6 illustrates a wiring diagram I may employ using normally closed solenoid switches and wherein the blower is eliminated since the solenoid coils are only energized or heated for the time necessary to disengage the solenoid switches at the completion of the plating period.

In this modification the solenoid switch contacts are connected with bus bars 26 and 27 by threaded lateral contact arms such as 32 and 33 as previously explained but the bar bridging the contact arms is normally in contact with the arms under spring pressure and is moved out of contact when the coil is energized. Clock switch 51 is connected to conductor 41 by a lead 76 and to bus bar 27 by a lead 77. In this instance the contacts of switch 51 at zero position are adapted to be engaged rather than disengaged and are disengaged at the other than zero position. Otherwise the operation is as previously explained whereby when arm 54 is moved to a position such as indicating fifteen minutes and switch 50 is engaged for either a six or twelve volt system'the solenoid switches will inter-connect bus bars 26 and 27 starting the plating cycle. Upon clock switch arm reaching zero position in its counter-clockwise movement the solenoid switch coils will be energized to overcome the spring pressure holding the solenoid switches closed and the plating current flow between bus bars 26 and 27 will be cut off and red signal lamp 49 will light and remain lighted as previously explained, until the operator disengages switch 50. In this case, the green signal light 48 may be connected to contact arm 32 by a lead 72 and to contact arm 33 by a lead 73 whereby it will light and remain lighted when the solenoid switches are engaged or when the plating process is in operation.

Although I prefer to use a clock switch of the type described to automatically control the plating period I contemplate that an interval timer may be omitted if desired in which case lead 56 (Figure 2) will be directly connected to lead 60 or lead 76 (Figure 6) will be directly connected to lead 77.

It will now be understood that I have provided a switch unit adapted to be used in the D. C. portion of an electroplating or the like system which is compact, relatively inexpensive due to the use of economical parts such as automotive type solenoid switches, and which is universal relative to a six or twelve volt plating system.

I wish it to be understood that I do not desire to be limited to the exact details of construction shown and described, for obvious modifications will occur to persons skilled in the art.

What I claim is as follows:

1. A switch unit adapted to be connected in series with the cathode lead from an electroplating tank and the low potential side of a source of direct current to control the flow of plating current through the tank, said unit comprising a pair of generally rectangular bus bars disposed in spaced generally parallel and longitudinally overlapping relation, one of said bus bars being adapted to be connected to the cathode lead and the other bus bar to the low potential direct current source, a plurality of housed electro-magnetic switches disposed between the bus bars, each switch comprising a pair of contact arms extending one from each side of the housing, a coil having a pair of spaced terminals extending from the housing, and a bridge bar adapted to connect the contact arms movable by energizing the coil, one contact arm of each switch being electrically and mechanically connected to one bus bar and the other contact arm being electrically and mechanically connected to the other bus bar whereby the bus bars are maintained in spaced relation and the switch is supported by the contact arms, the switches being arranged in banks, a first conductor connecting one coil terminal of each bank switch, a second conductor connecting the second coil terminal of each bank switch whereby the coils are connected in parallel across the conductors, one of said conductors being connected to one bus bar, and switch means supported by the bus bars adapted to connect the other conductor with the other bus bar whereby current may flow between the bus bars in parallel paths through the switches.

2. The switch unit as described in claim 1 and wherein the switch banks are arranged one above the other, and the switch means are adapted to connect the banks selectively in parallel and series across the bus bars.

3. The switch unit as described in claim 1 and wherein the switch means includes a double throw switch adapted to connect the banks selectively in parallel and series across the bus bars, and a manually settable time switch connected in series with one of said bus bars and adapted to break the circuit between the bus bars after a predetermined period.

4. The switch unit as defined in claim 1 and wherein a blower supported by a bus bar is adapted to direct cooling air between the bus bars and over the switches, the blower motor is connected across said other conductor and other bus bar, and the switch means includes a timer operated switch connected in series with said other conductor and said other bus bar and in parallel with said motor whereby opening of said switch will substantially interrupt the flow of plating current between the bus bars while the blower motor continues to operate.

5. A compact switch unit for controlling the flow of electroplating current from the cathode lead of a plating tank and the low potential side of a source of D. C. current, said unit comprising an elongate generally box form structure having a pair of spaced generally rectangular bus bars as its sidewalls, one bus bar being adapted to be connected to the cathode lead and the other to the low potential side of said source, a plurality of housed electro-magnetic switches disposed between the bus bars and detachably secured thereto by contact arms extending from each side of the housings, the contact arms for each switch being adapted to be bridged by a bar movable by an energizable coil, each switch coil having terminals extending from its associated housing, a conductor detachably secured to one terminal of each switch coil, a second conductor detachably secured to the other terminal of each switch coil whereby the coils will be connected in parallel across the conductors, one of said conductors being detachably secured to one bus bar, and switch means mounted on the structure adapted to connect the other conductor with the other bus bar whereby the switch coils will be concurrently energized to etfect flow of current between the bus bars in parallel paths through the switches.

No references cited. 

